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Assembly and spectroscopic interrogation of large atomic and molecular clusters in helium droplets

氦液滴中大原子和分子簇的组装和光谱询问

基本信息

批准号：
1664990
负责人：
Andrey Vilesov
金额：
$ 54.84万
依托单位：
University of Southern California
依托单位国家：
美国
项目类别：
Continuing Grant
财政年份：
2017
资助国家：
美国
起止时间：
2017-08-01 至 2021-09-30
项目状态：
已结题

来源：
https://www.nsf.gov/awardsearch/showAward?AWD_ID=1664990&HistoricalAwards=false
关键词：
Assembly spectroscopic interrogation large atomic

项目摘要

In this project funded by the Chemical Structure Dynamics and Mechanism (CSDM-A) program of the Chemistry Division, Professor Andrey Vilesov of The University of Southern California, interrogates chemical reactions at temperatures close to absolute zero (-460 °F). At such low temperatures, the internal motions of molecules are greatly slowed, making them easier to study. In order to study chemical reactions at such low temperatures, the atoms or molecules must be placed in an environment that keeps them cold, but also allows them to interact with each other. Since most common liquids freeze at such low temperatures, the atoms and molecules dissolved in them are prevented from colliding and interacting with each other. The PI overcomes these challenges by using helium droplets, which are still liquid at absolute zero, as test tubes in his studies. In his previous studies, Professor Vilesov made an additional interesting observation, namely that tiny vortices (similar to whirlpools) present in the helium droplets help form wire-shaped particles just a few atoms across. The properties and stability of such particles made of different materials are systematically studied with state of the art laser and cryogenic techniques. This project focuses on the mechanisms of aggregation of atoms and molecules at an ultra low temperature of 0.4 K. Free superfluid helium droplets up to 1 micrometer in diameter are doped with atoms or molecules, which then form clusters inside the droplet. The structure, stability and energy levels of the clusters are interrogated by laser spectroscopy, transmission electron microscopy and x-ray scattering techniques. Quantum vortices present in the superfluid droplets attract the imbedded particles serving as a template for low temperature aggregation. The properties of the resulting nanometer-thin, track-shaped clusters are in the focus of this project. In addition, this proposal includes the development of an experimental technique for the exploration of low temperature ion-molecule reactions using infrared spectroscopy and monitoring of the solvation effects in small carbocations and protonated water clusters. The broader impacts of this work include potential societal benefits from exploring unconventional paths for making useful nanomaterials. This project provides opportunities for training of undergraduate and graduate students in STEM field by developing of the cutting edge physical experiments and preparation of the ensuing publications.

在这个由化学部门化学结构动力学和机理（CSDM-A）项目资助的项目中，南加州大学的Andrey Vilesov教授在接近绝对零度（-460°F）的温度下研究化学反应。在如此低的温度下，分子的内部运动大大减缓，使它们更容易研究。为了在如此低的温度下研究化学反应，原子或分子必须被置于一个既能保持低温，又能让它们相互作用的环境中。由于大多数普通液体在如此低的温度下结冰，溶解在其中的原子和分子就无法相互碰撞和相互作用。在他的研究中，PI通过使用在绝对零度下仍然是液体的氦滴作为试管来克服这些挑战。在他之前的研究中，Vilesov教授做了另外一个有趣的观察，即存在于氦滴中的微小漩涡（类似于漩涡）有助于形成只有几个原子大小的线状粒子。利用先进的激光和低温技术系统地研究了由不同材料制成的这种粒子的性质和稳定性。本项目主要研究在0.4 K的超低温下原子和分子的聚集机制。直径达1微米的自由超流氦液滴被掺杂了原子或分子，然后在液滴内部形成团簇。通过激光光谱学、透射电子显微镜和x射线散射技术对团簇的结构、稳定性和能级进行了研究。超流体液滴中存在的量子涡旋吸引嵌入的粒子，作为低温聚集的模板。由此产生的纳米薄轨道状簇的性质是本项目的重点。此外，该提案还包括开发一种实验技术，用于利用红外光谱探索低温离子-分子反应，并监测小碳正离子和质子化水团簇的溶剂化效应。这项工作更广泛的影响包括探索制造有用纳米材料的非常规途径所带来的潜在社会效益。该项目通过开展前沿物理实验和准备后续出版物，为STEM领域的本科生和研究生提供培训机会。

项目成果

期刊论文数量（16）

专著数量（0）

科研奖励数量（0）

会议论文数量（0）

专利数量（0）

Formation of Core–Shell Ethane–Silver Clusters in He Droplets

氦液滴中核心-壳层乙烷-银团簇的形成

DOI：
10.1021/acs.jpca.7b05136
发表时间：
2017
期刊：
The Journal of Physical Chemistry A
影响因子：
0
作者：
Loginov, Evgeny;Gomez, Luis F.;Sartakov, Boris G.;Vilesov, Andrey F.
通讯作者：
Vilesov, Andrey F.

Disintegration of diminutive liquid helium jets in vacuum

小型液氦射流在真空中的分解

DOI：
10.1063/5.0004503
发表时间：
2020
期刊：
The Journal of Chemical Physics
影响因子：
0
作者：
Tanyag, Rico Mayro P.;Feinberg, Alexandra J.;O’Connell, Sean M. O.;Vilesov, Andrey F.
通讯作者：
Vilesov, Andrey F.

Experiments with Large Superfluid Helium Nanodroplets

大型超流氦纳米液滴实验